Fix bugs regarding clamping of numFrames variable.

there is a clamping value in getDurationUsIfPlayedAtSampleRate function
numFrames parameter is uint32_t type. when return value, cast uint32_t to int32_t.
that make clamp value of numFrames

Signed-off-by : Hyoungjun Byun <hyoungjun.byun@lge.com>

Change-Id: Ib97d89b33a8e5b6bea3d499e4b44d1056d7fae66
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
index be116e3..4992137 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
@@ -1145,8 +1145,8 @@
         ALOGE("sampleRate is 0 in %s mode", offloadingAudio() ? "offload" : "non-offload");
         return 0;
     }
-    // TODO: remove the (int32_t) casting below as it may overflow at 12.4 hours.
-    return (int64_t)((int32_t)numFrames * 1000000LL / sampleRate);
+
+    return (int64_t)(numFrames * 1000000LL / sampleRate);
 }
 
 // Calculate duration of pending samples if played at normal rate (i.e., 1.0).